This is al-Qa'eda Rule 18: 'You must claim you were tortured'

Feroz Abbasi, Martin Mubanga, Moazzam Begg and Richard Belmar finally arrived back in Britain last week after their three-year imprisonment in Guantanamo, to near-universal acclaim and sympathy. Their lawyers insist that they are totally innocent of any involvement in terrorism. The men themselves say that they have been tortured, and that the admissions made by three of them – that they had been recruited by al-Qa'eda , and undergone training in terrorist camps in Afghanistan – are completely false.

The horrors of what undoubtedly took place in Abu Ghraib, the prison in Iraq, have convinced many people that the Americans must also have administered hideous tortures to everyone they imprisoned at Guantanamo. In fact it is not at all clear that the Americans have tortured anyone in Guantanamo. Some of the "sexual tortures" – women interrogators rubbing their breasts against the backs of those being questioned – sound, to Western ears, too close to the comfy chair of Monty Python's Spanish Inquistion to be taken seriously. Surprisingly, perhaps, the US army authorities took them very seriously: they dismissed for "inappropriate conduct" a female interrogator who was found to have run her fingers through one detainee's hair and sat on his lap during an interrogation.

The detainees in Guantanamo were certainly humiliated and made to feel extremely uncomfortable. They may have been deprived of light and sleep and forced to stand for long periods. But did it constitute torture? The US Department of Defence insists that none of the Britons even alleged they had been tortured or abused until October last year – and that when US officials investigated those claims, they not only found they had no foundation, but that one of the Britons had assaulted one of his interrogators.

The men's claim that they were tortured at Guantanamo should also be set in the context of the al-Qa'eda training manual discovered during a raid in Manchester a couple of years ago. Lesson 18 of that manual, whose authenticity has not been questioned, emphatically states, under the heading "Prison and Detention Centres", that, when arrested, members of al-Qa'eda "must insist on proving that torture was inflicted on them by state security investigators. [They must] complain to the court of mistreatment while in prison". That is not, of course, proof that the Britons were not tortured in Guantanamo. But it ought to encourage some doubts about uncritically accepting that they were – which seems to be the attitude adopted by most of the media.

Whether or not it was exacted by torture, the evidence of the British detainees' involvement in terrorism seems to have been part of what pushed our Government into drafting a law that will allow it to place British citizens under house arrest indefinitely, without trial or charge. It is ironic that the Government that promised to "free the citizen" by adopting the European Convention on Human Rights should now be introducing such a measure. The glorious era of the Human Rights Act was not supposed to usher in the ignominious epoch of the indefinite suspension of habeas corpus. But that is what has happened – as indeed one of the Law Lords predicted it would.

When they were called on to decide whether the indefinite detention of the "Belmarsh Nine" – the foreign terrorist suspects imprisoned here without trial – was compatible with the Human Rights Act, the majority of the Law Lords decided that it was not. But Lord Hoffmann demurred. He did not want, he said, to give "the impression that all that was necessary [to make indefinite detention without trial acceptable] was to extend the power to United Kingdom citizens as well". The majority decision was that the law violated the Human Rights Act because it applied only to foreigners and was therefore "discriminatory". This decision implied that the power of detention would be acceptable if it applied to everyone. The Home Secretary duly took the hint – and we now face a law that even his predecessor, David Blunkett, thinks is "so draconian it is difficult to justify".

Desperate situations call for desperate remedies. Charles Clarke, the Home Secretary, is right to assert that the threats from al-Qa'eda are real – there are indeed groups of Islamic fundamentalists in Britain who want to kill thousands of people. Mr Clarke thinks that the threat justifies giving himself the power to place British citizens under indefinite house arrest. The view that this grotesquely exaggerates the threat has penetrated the pinnacles of the establishment. Lord Hoffmann, for instance, has claimed that "the real threat to the life of the nation… comes not from terrorism but from laws like these".

That phrase, though increasingly popular, is in fact a piece of empty rhetoric. An al-Qa'eda bomb detonated in the centre of Whitehall, for instance, could well be a threat to the life of the nation. Indefinite house arrest without trial of those suspected of involvement in terrorism, while it would certainly be a deprivation of liberty for the individual who was detained, would not be a threat to the life of our nation. The policy of internment without trial has been followed in the past – in Northern Ireland in the 1970s, and during the Second World War – without permanently damaging the constitution, the rule of law, or the cause of liberty in Britain.

The real issue with Mr Clarke's proposed law is a practical one: is it actually the way to deal with the terrorist threat? He himself does not sound wholly convinced that it is. He asked for a "debate", and it seems eminently possible that, at the end of it, he will shy away from indefinite house arrest for anyone. Alternatives certainly exist. The Government could, for example, change the rules of evidence in terrorist trials to make it easier to convict defendants, or to hear the evidence against them without compromising the secret sources that gathered it.

The Government has dismissed those alternatives. It is not clear why. The Home Office has changed the rules of evidence to make conviction easier in other areas – for example, sexual crimes. Uncorroborated testimony is sufficient to convict in cases of child sex abuse; and in rape cases, the Government passed a law to prevent defendants or their lawyers from cross-examining their accusers about their sexual history.

Changing the rules of evidence to facilitate terrorist convictions would be less damaging to our legal traditions than the proposed suspension of habeas corpus. Defendants would at least be able to know the charges against them, and to offer a defence – and the Government would be able to see them sentenced to judicially sanctioned terms of imprisonment. Of course Charles Clarke's draconian alternative will not "threaten the life of the nation". But it will be an unnecessary blot on the administration of justice. The next edition of the al-Qa'eda manual may well refer to it as one of their victories.